This invention relates to radio communications and more specifically to a radio frequency (RF) mixer circuit and method used in RF equipment.
RF communication equipment generally use mixers to convert a signal from a low frequency to a high frequency or a high frequency to a low frequency by mixing the signal with a local oscillator (LO) signal. The LO frequency can be above or below the frequency of a desired signal to produce a sum and a difference frequency one of which is the frequency of interest.
Mixer performance is critical to the overall performance of transmit and receive channels of RF equipment that employ mixers. It is especially critical in receiver applications where a broadband signal carrying numerous sub-channels are to be detected and processed. In such applications, multiple mixers serve to separate each sub-channel from a broadband composite signal for separate digital processing of the sub-channels.